AIS receiver based on superheterodyne principle

Abstract

The invention relates to an AIS receiver based on the superheterodyne principle. The AIS receiver taking the FPGA as a control core comprises a simulation front-end module, a primary frequency mixing module, a secondary frequency mixing module, a base band demodulation module, a PLL module, a clock management module, a power supply management module, an FPGA controller module and a serial port driver module. According to the invention, by use of a low-noise amplifier and an AGG circuit, the dynamic range is wide, weaker signals can be captured, and ships in the longer distance can be detected; by use of an intermediate frequency signal processing chip with quite high demodulation sensitivity, the sensitivity of the receiver is further improved; by use of the CMX7042, demodulation, decoding and verification of base band signals are achieved, system design is simplified, and cost is controlled; and temperature-compensation crystal oscillators are used for supplementing the system clock, and a clock fan-out chip is used for carrying out unified distribution, synchronization of the system is achieved, output frequency stability of a phase-locked loop is improved and precision of the system is further improved.

Description

technical field [0001] The invention relates to an AIS (ship automatic identification system) receiver based on the superheterodyne principle. Background technique [0002] AIS is a device that uses radio means to send and receive static and dynamic information of ships within the working range of VHF radio. It is used for communication between ships and ships, and between ships and base stations to ensure that the base stations The tracking and monitoring between ships and ships has greatly improved the safety of ocean navigation and inland navigation. The main purpose of installing the AIS system for ships and ship supervision departments is to avoid ship collisions, realize automatic ship identification, assist target tracking, simplify information exchange, etc., so as to understand the traffic conditions of the current channel. Of course, the application of AIS has also expanded in recent years. On many occasions. [0003] Compared with the traditional ship collisio...

AI Technical Summary

Problems solved by technology

[0006] Although AIS technology is relatively mature, there are still many technical problems to be solved

First of all, most of the traditional AIS receivers are targeted and can only specifically receive Class A AIS signals or Class B AIS signals; secondly, the distance that the existing AIS receivers can receive AIS signals is limited; moreover, the AIS system’s The bit error rate can be further reduced; finally, the fusion technology of AIS and radar signals remains to be studied

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